Support nullable types.

Support IEnumerable properties in objects (serializes to string).

.vs/ProjectSettings.json

@@ -0,0 +1,3 @@
+{
+  "CurrentProjectSetting": null
+}

Logic/Common.cs

@@ -1,3 +1,5 @@
+using Newtonsoft.Json;
+using System.Collections;
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations.Schema;
 using System.Linq;
@@ -14,7 +16,17 @@ public static DataTable GetDataTableFromFields<T>(IEnumerable<T> data, SqlBulkCo
             foreach (PropertyInfo propertyInfo in listType.GetProperties())
             {
                 var columnName = GetColumnName(propertyInfo);
-                dt.Columns.Add(columnName, propertyInfo.PropertyType);
+
+                if (propertyInfo.PropertyType.IsNonStringEnumerable())
+                {
+                    dt.Columns.Add(columnName, typeof(string));
+                }
+                else
+                {
+                    dt.Columns.Add(columnName, Nullable.GetUnderlyingType(propertyInfo.PropertyType) ?? propertyInfo.PropertyType);
+                }
+
+
                 sqlBulkCopy.ColumnMappings.Add(columnName, columnName);
             }
 
@@ -24,7 +36,15 @@ public static DataTable GetDataTableFromFields<T>(IEnumerable<T> data, SqlBulkCo
                 foreach (PropertyInfo propertyInfo in listType.GetProperties())
                 {
                     var columnName = GetColumnName(propertyInfo);
-                    dr[columnName] = propertyInfo.GetValue(value, null);
+
+                    if (propertyInfo.PropertyType.IsNonStringEnumerable())
+                    {
+                        dr[columnName] = JsonConvert.SerializeObject(propertyInfo.GetValue(value, null));
+                    }
+                    else
+                    {
+                        dr[columnName] = propertyInfo.GetValue(value, null) ?? DBNull.Value;
+                    }
                 }
                 dt.Rows.Add(dr);
             }

Logic/Extensions.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+using System.Threading.Tasks;
+
+public static class Extensions
+{
+    public static bool IsNonStringEnumerable(this PropertyInfo pi)
+    {
+        return pi != null && pi.PropertyType.IsNonStringEnumerable();
+    }
+
+    public static bool IsNonStringEnumerable(this object instance)
+    {
+        return instance != null && instance.GetType().IsNonStringEnumerable();
+    }
+
+    public static bool IsNonStringEnumerable(this Type type)
+    {
+        if (type == null || type == typeof(string))
+            return false;
+        return typeof(IEnumerable).IsAssignableFrom(type);
+    }
+}

Logic/Logic.csproj

@@ -30,6 +30,9 @@
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
   <ItemGroup>
+    <Reference Include="Newtonsoft.Json, Version=10.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed, processorArchitecture=MSIL">
+      <HintPath>..\packages\Newtonsoft.Json.10.0.3\lib\net45\Newtonsoft.Json.dll</HintPath>
+    </Reference>
     <Reference Include="System" />
     <Reference Include="System.ComponentModel.DataAnnotations" />
     <Reference Include="System.Core" />
@@ -41,10 +44,14 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Common.cs" />
+    <Compile Include="Extensions.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="SimpleSqlBulkUpdate.cs" />
     <Compile Include="SimpleSqlBulkCopy.cs" />
   </ItemGroup>
+  <ItemGroup>
+    <None Include="packages.config" />
+  </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.

Logic/SimpleSqlBulkCopy.cs

@@ -105,7 +105,6 @@ public void Dispose()
             sqlBulkCopy = null;
         }
 
-
         public void WriteToServer<T>(string destinationTableName, IEnumerable<T> data)
         {
             sqlBulkCopy.DestinationTableName = destinationTableName;

Logic/packages.config

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<packages>
+  <package id="Newtonsoft.Json" version="10.0.3" targetFramework="net451" />
+</packages>